Warning sign



FIG. 1 is a perspective view of a warning sign showing our new design;

FIG. 2 is a second perspective view disclosing the opposite of that seen in FIG. 1;

FIG. 3 illustrates an elevated second side view thereof;

FIG. 4 illustrates an elevated front view thereof;

FIG. 5 illustrates an elevated first side view thereof; and,

FIG. 6 is an elevated second side view thereof.

The broken line showing of indicia and symbols is included for the purpose of illustrating portions of the “article” and forms no part of the claimed design. 

CLAIM The ornamental design for a warning sign, as shown and described. 